diff options
Diffstat (limited to 'test/packetdrill/tests/linux/pmtu_discovery/pmtud-10pkt-1460-to-1160.pkt')
| -rw-r--r-- | test/packetdrill/tests/linux/pmtu_discovery/pmtud-10pkt-1460-to-1160.pkt | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/test/packetdrill/tests/linux/pmtu_discovery/pmtud-10pkt-1460-to-1160.pkt b/test/packetdrill/tests/linux/pmtu_discovery/pmtud-10pkt-1460-to-1160.pkt new file mode 100644 index 0000000..df30dee --- /dev/null +++ b/test/packetdrill/tests/linux/pmtu_discovery/pmtud-10pkt-1460-to-1160.pkt @@ -0,0 +1,54 @@ +// Test Path MTU discovery, RFC 1191. +// This is a more substantive case, with 10*original_mss to send. +// In this variant, we get an ICMP "unreachable frag_needed mtu 1200" +// message and because the TCP sequence number is valid, TCP +// immediately retransmits 'cwnd' packets using a smaller MSS +// based on the MTU from the ICMP message. + +// Establish a connection. +0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0.000 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0.000 bind(3, ..., ...) = 0 +0.000 listen(3, 1) = 0 + +0.100 < S 0:0(0) win 32792 <mss 1460,nop,wscale 7> +0.100 > S. 0:0(0) ack 1 <mss 1460,nop,wscale 6> +0.200 < . 1:1(0) ack 1 win 257 +0.200 accept(3, ..., ...) = 4 + +// Send 10 data segments. +0.200 write(4, ..., 14600) = 14600 +0.200 > P. 1:14601(14600) ack 1 + +// ICMP says that the first segment was too big. +0.250 < [1:1461(1460)] icmp unreachable frag_needed mtu 1200 +// TCP picks a packet size using the MTU from the message, and +// retransmits 'cwnd' packets: +0.250 > . 1:1161(1160) ack 1 +0.250 > . 1161:2321(1160) ack 1 +0.250 > . 2321:3481(1160) ack 1 +0.250 > . 3481:4641(1160) ack 1 +0.250 > . 4641:5801(1160) ack 1 +0.250 > . 5801:6961(1160) ack 1 +0.250 > . 6961:8121(1160) ack 1 +0.250 > . 8121:9281(1160) ack 1 +0.250 > . 9281:10441(1160) ack 1 +0.250 > . 10441:11601(1160) ack 1 + +// ACKs for packets retransmitted at a smaller MSS release yet more packets... + +0.350 < . 1:1(0) ack 1161 win 257 +0.350 > . 11601:12761(1160) ack 1 +0.350 > . 12761:13921(1160) ack 1 + +0.355 < . 1:1(0) ack 2321 win 257 +0.355 > P. 13921:14601(680) ack 1 + +// Receiver ACKs all data. +0.455 < . 1:1(0) ack 14601 win 257 + +// Clean up. +0.500 close(4) = 0 +0.500 > F. 14601:14601(0) ack 1 +0.600 < F. 1:1(0) ack 14602 win 257 +0.600 > . 14602:14602(0) ack 2 |